1. Field of the Invention
The invention relates to a hydraulic vibration damper, and more particularly, to a hydraulic vibration damper with an adjustable damping valve.
2. Description of the Prior Art
The prior art includes vibration dampers such as those in German Laid-Open Patent Application No. DEOS 29 11 768, in which control is exercised by means of electromagnets and also by means of which the damping force can be adjusted at a low piston velocity. A disadvantage is that no change of the damping forces is possible at medium and high piston velocities. Since the piston rod in this arrangement can only open or close a corresponding bypass, no valve force changes at medium piston velocity are possible. Therefore, this arrangement is designed as a bypass valve, and can only be used in connection with a conventional damping force regulation.
Vibration dampers or shock absorbing legs are also known, such as in German Laid Open Patent Application No. DE-OS 32 31 739, in which the damping force can be changed. However, with this apparatus, there is an active bypass valve with a controllable cross-section modification parallel to the damping valves. This bypass valve system is intended for easy installation in the available space of a vibration damper.